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A Fault Diagnosis Method for Turn-to-Turn Short Circuit of Induction Motor Driven by Frequency Converter

A technology for inter-turn short-circuit faults and induction motors, which is applied in the direction of motor generator testing, instruments, and electrical measurement. It can solve problems such as not being suitable for long-term online use, different detection effects, and difficult to unify fault indicators. Low parameter requirements, real-time diagnosis, and wide application range

Inactive Publication Date: 2017-07-25
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the extra injected signal will not only generate high-frequency noise, but also increase software burden and increase motor loss, which is not suitable for long-term online use
[0006] In addition, the frequency conversion speed control system has a variety of pulse width modulation (PWM), common ones include sinusoidal modulation (SPWM) and vector modulation (SVPWM), these modulations have different impacts on detection, few in the prior art concerned about this issue
At the same time, due to the lack of derivation of the theoretical model of the motor, it is difficult to achieve the unification of fault indicators in various operating modes in frequency conversion and speed regulation for the above technologies using zero-sequence voltage detection

Method used

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  • A Fault Diagnosis Method for Turn-to-Turn Short Circuit of Induction Motor Driven by Frequency Converter
  • A Fault Diagnosis Method for Turn-to-Turn Short Circuit of Induction Motor Driven by Frequency Converter
  • A Fault Diagnosis Method for Turn-to-Turn Short Circuit of Induction Motor Driven by Frequency Converter

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] This embodiment takes a Y-connected 4kW three-phase induction motor with an inter-turn short circuit in phase A as an example, and when the carrier frequency is f c Under the inverter driving condition of =4kHz, the fault index calculation model of generalized high-frequency excitation is derived.

[0030] When the inter-turn short circuit occurs in phase A of the induction motor, the motor model at this time is:

[0031] v abcs =R s i abcs +p(L s i abcs +L sr1 i abcr1 +L sr3 i abcr3 ) (1)

[0032] Among them, v abcs is the three-phase voltage matrix relative to point s, i abcs is the three-phase stator current matrix, i abcr1 is the fundamental plane three-phase rotor current matrix, R s is the stator resistance matrix, L s is the stator inductance matrix, L sr1 is the stator-rotor mutual inductance matrix of the fundamental harmonic plane, L sr3 is the stator-rotor mutual inductance matrix of the third harmonic plane,

[0033] According to the defin...

Embodiment 2

[0054] In this embodiment, according to the actual operating conditions of the inverter, the high frequency f is selected from the harmonics of the inverter itself h As an incentive source, the steps are as follows:

[0055] According to the binary Fourier series, the A-phase voltage of the asymmetric regular sampling (SPWM) relative to the midpoint z of the bus voltage can be obtained expression for:

[0056]

[0057] Among them, u dc is half of the DC bus voltage, such as figure 2 shown in . m, n are the harmonic times of the carrier signal and the modulating wave signal respectively, f c is the carrier signal frequency, f 1 is the modulation wave signal frequency, q=m+n(f 1 / f c ), M is the modulation ratio, θ c , θ 1 is the phase angle of carrier wave and modulating wave, J n is a Bessel function of the first kind with base n.

[0058] Similarly, the seven-segment symmetrical regular vector modulation (SVPWM) can be obtained

[0059]

[0060] in,

[...

Embodiment 3

[0069] like figure 1 As shown, the following steps of the inverter-driven induction motor stator turn-to-turn short circuit fault diagnosis method:

[0070] (1) Connect the midpoint z of the DC bus capacitor and the midpoint s of the induction motor to the input terminal of the voltage sensor to collect the voltage v sz , the sampling frequency is 50kHz, specifically:

[0071] like figure 2 As shown, according to the motor zero-sequence voltage formula, relative to the motor neutral point zero-sequence voltage v 0s expression:

[0072]

[0073] where v as , v bs , v cs For the phase voltage relative to the neutral point s of the induction motor, there are:

[0074]

[0075] Among them, v sz It is the voltage between the neutral point s of the induction motor and the midpoint z of the DC bus capacitor. In this scheme, it is the voltage measured by the sensor. Further algebraic operations can be obtained:

[0076]

[0077] where v az , v bz , v cz For the p...

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Abstract

The invention discloses a transducer drive induction motor stator turn-to-turn short circuit fault diagnosis method; the method calculation is simple, easy to realize and has high robustness, the parameter requirement to the induction motor is low. A voltage sensor is added, the transducer switch sideband harmonic wave zero-sequence component is extracted and analyzed for detecting the fault of the ring opening and closing operation and speed regulation operation for the motor system, the method is suitable for the modulation modes as SPWM, SVPWM, the application range is wide, the dynamic effect is good, the recognition precision is high, the stator turn-to-turn short circuit fault can be diagnosed at real time for giving the fault degree index.

Description

technical field [0001] The invention relates to the technical field of fault diagnosis, in particular to a method for diagnosing a short-circuit fault between turns of an induction motor stator. Background technique [0002] In the industrial field, the induction motor is the most widely used motor type, which has the characteristics of simple structure, low price, and good robustness. However, due to problems such as the manufacturing process and the on-site environment, problems such as local overheating of the stator and performance degradation of insulation components will occur in the running motor. The common transient overvoltage in the frequency conversion speed control system further accelerates the aging process, thus causing the stator fault of the motor. It is generally believed in the industry that serious stator faults start from early stator inter-turn short circuits. [0003] The fault diagnosis technology of induction motor is an effective solution to the a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/02G01R31/34
Inventor 黄进刘赫侯招文王彤赵力航
Owner ZHEJIANG UNIV
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